1. Field of the Invention
The present invention relates generally to computer networks, and more specifically, to a method and apparatus for detecting and recovering from link failures.
2. Background Information
Many organizations, including businesses, governments and educational institutions, utilize computer networks so that employees and others may share and exchange information and/or resources. A computer network typically comprises a plurality of entities interconnected by means of one or more communications media. An entity may consist of any device, such as a computer, that “sources” (i.e., transmits) or “sinks” (i.e., receives) messages over the communications media. A common type of computer network is a local area network (“LAN”) which typically refers to a privately owned network within a single building or campus. LANs typically employ a data communication protocol (LAN standard), such as Ethernet, or a wireless protocol, that defines the functions performed by data link and physical layers of a communications architecture (i.e., a protocol stack).
One or more intermediate network devices are often used to couple LANs together and allow the corresponding entities to exchange information. For example, a bridge or switch may be used to provide a “switching” function between two or more LANs or end stations. Typically, the bridge or switch is a computer and includes a plurality of ports that are coupled to LANs and end stations, such as servers and hosts, as well as to other bridges and/or routers. Ports used to couple bridges to each other are generally referred to as a trunk ports, whereas ports used to couple bridges to LANs and end stations are generally referred to as access ports. The bridging function includes receiving data from a sending entity at a source port, and transferring that data to at least one destination port for forwarding to one or more receiving entities.
In a typical network design, a plurality of access switches are disposed in a wiring closet. The access switches are coupled to the workstations and servers of an enterprise or organization. The access switches from several wiring closets are then connected by uplinks to a plurality of distribution switches. The distribution switches, in turn, are connected to core switches so that the workstations and servers associated with the first wiring closet can access information and services available in other parts of the enterprise or organization.
Each switch of a computer network generally requires some configuration, which can be time-consuming and error prone. Thus, it is desirable to simplify the network design, and reduce the amount of network configuration that must be performed.